All this argument concerning the unearned increment may be carried over, with scarcely a change of phrase, to the case of "capital goods." The Danish flint supply was of first-rate economic consequence, for a thousand years or so, during the stone age; and the polished-flint utensils of that time were then "capital goods" of inestimable importance to civilisation, and were possessed of a "productivity" so serious that the life of mankind in that world may be said to have been balanced on the fine-ground edge of those magnificent polished-flint axes. All that lasted through its technological era. The flint supply and the mechanical expedients and "capital goods," whereby it was turned to account, were valuable and productive then, but neither before nor after that time. Under a changed technological situation the capital goods of that time have become museum exhibits, and their place in human economy has been taken by technological expedients which embody another "state of the industrial arts," the outcome of later and different phases of human experience. Like the polished-flint ax, the metal utensils which gradually displaced it and its like in the economy of the Occidental culture were the product of long experience and the gradual learning of ways and means. The steel ax, as well as the flint ax, embodies the same ancient technological expedient of a cutting edge, as well as the use of a helve and the efficiency due to the weight of the tool. And in the case of the one or the other, when seen in historical perspective and looked at from the point of view of the community at large, the knowledge of ways and means embodied in the utensils was the serious and consequential matter. The construction or acquisition of the concrete "capital goods" was simply an easy consequence. It "cost nothing but labor," as Thomas Mun would say.